In recent years, in a factory manufacturing line, in place of a line production system suitable for mass production, the number of cell production systems which realize a production of multiple models in smaller lots which flexibly copes with needs of customers has been increasing. In the cell production system, one worker processes a plurality of working steps and produces one product (or a part of a product) in a working place called a cell for production. In the cell production system, there is also a case where a parts assembling operation to a work by the worker is executed by a robot cell in place of the worker and the cell production system is constructed by the robot cell.
In the robot cell, it is necessary that the precise and complicated assembling operation of a high difficulty degree which is executed by the worker is performed by a robot in place of the worker. For this purpose, there is a case where such robot control that a force sensor is provided for the robot and, while making force control, a work is assembled or the robot shifts a tool from one hand to the other in accordance with the work to be assembled and executes the operation is used.
In the robot system such as a robot cell, there is such a demand that the operator wants to store operation information for a period of time as long as possible for the purpose of performing an analyzing operation when a fault occurs. The operation information denotes sensor information such as outputs of an encoder and a force sensor arranged at each position such as a joint or the like besides control information of joints and an end effector of a robot arm and control information of various kinds of tools. A data file or a data stream of such operation information is generally called “log” or the like. There is a case where a transfer or a recording process of the operation information is called “logging” or the like. The logging of the operation information is performed to a storage device such as disk device, flash memory, or the like arranged in a control unit of the robot or the operation information is transferred and stored through a network into an external managing terminal of the robot device.
A data amount of the operation information increases in association with complexity of the assembling operation, the longer an operating period of time of the system is, such a data amount increases in association with it, and a load of a robot control unit or a network or an external managing terminal also increases due to the logging. In consideration of such a point, for example, such a construction that in at least either a case where a size of the operation information of the robot reaches a predetermined amount or a case where a predetermined time has passed, the operation information is transmitted to the external managing terminal through a communication network unit has been proposed (for example, the following Patent Literature 1).